X-ray computed tomography (CT) image reconstruction involves obtaining raw data representing a difference between X-ray attenuation degrees of tissues of a human body by projecting X-rays to the human body from the outside in several directions and reconstructing an image of the inside of a human body by using the raw data. X-ray CT image reconstruction may obtain a high-resolution image within a shorter period of time, as compared with other systems used to obtain images of the inside of the human body, such as positron emission tomography (PET), magnetic resonance imaging (MRI), and single photon emission computed tomography (SPECT). However, when a moving object is scanned using an X-ray CT system, motion artifacts occur, and thus the quality of an image is degraded.